This invention relates to an air conditioning system using an air cycle.
There is conventionally known a cooling system operating through an air cycle, as disclosed in Japanese Unexamined Patent Publication No. 62-102061. A cooling system of this kind includes a compressor, a heat exchanger and an expander, and is configured to suck an air into the compressor for compression, cool the compressed air in the heat exchanger and then expand it in the expander thereby obtaining a low-temperature air.
Meanwhile, in the cooing system disclosed in the above publication, a vapor isolating device using a vapor isolating membrane is provided between the heat exchanger and the expander to isolate moisture from the compressed air being supplied to the expander. Once expanded in the expander, the air is reduced in temperature so that dropwise condensation may occur in the air. Therefore, the air as a working fluid for the air cycle is needed to undergo dehumidification prior to entry into the expander. For this reason, in the above cooling system, the vapor isolating device is provided in place to dehumidify the compressed air.
However, since the cooling system as described above accomplishes dehumidification by using the vapor isolating membrane, the air as a working fluid for the air cycle can only be dehumidified between the compressor and the expander. Specifically, when the vapor isolating membrane is used, moisture in the air permeates the vapor isolating membrane, i.e., moves from the air on one side of the vapor isolating membrane to that on the other side. In this case, the moisture in the air permeates the vapor isolating membrane with a difference between vapor partial pressures in the airs on both sides of the isolating membrane. Accordingly, the air from which moisture moves must always be held at a higher vapor partial pressure than that to which moisture moves, and therefore there has been nothing for means for dehumidification but to be provided in a place where the vapor partial pressure of the air from which moisture moves will be high, i.e., between the compressor and the expander.
It is now to be noted that any component for dehumidifying the air, including one using the vapor isolating membrane, should be rather large in size. This is because a certain degree or more of contact area with the air to be dehumidified must be ensured. Therefore, there arises the problem that limitation of placement of such a relatively large component would incur degradation in design flexibility of the overall system.
In addition, if a seal between the compressor and the expander is insufficient, this causes leakage of the compressed air so that the compressor input may be lost, resulting in significantly decreased efficiency. Therefore, as the number of components provided between the compressor and the expander increases, the number of points at which leakage of the compressed air may occur, such as connecting parts, also increases. There arises the problem that attempts to fully form the seal would incur complicated construction.
The present invention has been made in view of such problems and therefore aims at enhancing the design flexibility and providing simplified construction while keeping high efficiency.
The present invention provides for carrying out dehumidification of the air as a working fluid for the air cycle with the use of a humidity medium for absorbing and releasing moisture through contact with the air prior to supply of the air to the compressor.
More specifically, a first solution taken in the present invention is directed to an air conditioning system for effecting air conditioning in an air cycle comprising a compressor (21), a heat exchanger (30) and an expander (22). Further, provided in this system is dehumidifying means (60) that includes a humidity medium for absorbing and releasing moisture through contact with an air and allows the humidity medium to absorb moisture in a primary air to be supplied to the compressor (21) while releasing the moisture therein to a secondary air thereby continuously dehumidifying the primary air.
In a second solution taken in the present invention, based on the first solution, the heat exchanger (30) is arranged to cool the compressed primary air through heat exchange with the secondary air, and the dehumidifying means (60) is arranged to release moisture in the humidity medium to the secondary air coming from the heat exchanger (30).
In a third solution taken in the present invention, based on the first or second solution, the humidity medium of the dehumidifying means (60) is provided with a solid adsorbent for adsorbing moisture.
In a fourth solution taken in the present invention, based on the third solution, the humidity medium of the dehumidifying means (60) is formed of a rotor member (61) that is formed in the shape of a disc to allow air passage in a direction of its thickness and provides contact of the passing air with the solid adsorbent, and the dehumidifying means (60) comprises a moisture absorbing section (62) where the rotor member (61) absorbs moisture in the primary air through contact with the primary air, a moisture releasing section (63) where the rotor member (61) releases moisture therein to the secondary air through contact with the secondary air, and a drive mechanism for rotatively driving the rotor member (61) to allow the rotor member (61) to move between the moisture absorbing section (62) and the moisture releasing section (63).
In a fifth solution taken in the present invention, based on the third solution, the solid adsorbent is made of porous inorganic oxide.
In a sixth solution taken in the present invention, based on the first or second solution, the humidity medium of the dehumidifying means (60) comprises a liquid absorbent for absorbing moisture.
In a seventh solution taken in the present invention, based on the first solution, the humidity medium of the dehumidifying means (60) comprises a liquid absorbent for absorbing moisture, and the dehumidifying means (60) is arranged so that the liquid absorbent is heated by the primary air coming from the compressor (21) to release moisture having absorbed from the primary air to the secondary air.
In an eighth solution taken in the present invention, based on the sixth or seventh solution, the dehumidifying means (60) includes a moisture-permeable, hydrophobic porous membrane and is arranged to contact the liquid absorbent with the primary air through the hydrophobic porous membrane.
In a ninth solution taken in the present invention, based on the sixth or seventh solution, the liquid absorbent is made of a water solution of hydrophilic organic compound.
In a tenth solution taken in the present invention, based on the sixth or seventh solution, the liquid absorbent is made of a water solution of metallic halide.
In an eleventh solution taken in the present invention, based on the sixth or seventh solution, the dehumidifying means (60) comprises a circulation circuit (64) that includes a moisture absorbing section (65) for contacting the liquid absorbent with the primary air and a moisture releasing section (66) for contacting the liquid absorbent with the secondary air and circulates the liquid absorbent between the moisture absorbing section (65) and the moisture releasing section (66).
In a twelfth solution taken in the present invention, based on the second solution, cooling of a room is effected by supplying the primary air expanded in the expander (22) to the room.
In a thirteenth solution taken in the present invention, based on the twelfth solution, the primary air is an outside air taken from outdoors and then supplied to the room through the expander (22), while the secondary air is a room air taken from the room and then discharged to outdoors through the dehumidifying means (60).
In a fourteenth solution taken in the present invention, based on the twelfth solution, the primary air is an outside air taken from outdoors and then supplied to the room through the expander (22), while the secondary air is an outside air taken from outdoors and then discharged to outdoors through the dehumidifying means (60).
In a fifteenth solution taken in the present invention, based on the twelfth solution, the primary air is a room air taken from the room and then supplied to the room through the expander (22), while the secondary air is a room air taken from the room and then discharged to outdoors through the dehumidifying means (60).
In a sixteenth solution taken in the present invention, based on the twelfth solution, the primary air is a room air taken from the room and then supplied to the room through the expander (22), while the secondary air is an outside air taken from outdoors and then discharged to outdoors through the dehumidifying means (60).
In a seventeenth solution taken in the present invention, based on the twelfth solution, the primary air is a mixed air of a room air taken from the room and an outside air taken from outdoors and is supplied to the room through the expander (22), while the secondary air is a room air taken from the room and then discharged to outdoors through the dehumidifying means (60).
In an eighteenth solution taken in the present invention, based on the twelfth solution, the primary air is a mixed air of a room air taken from the room and an outside air taken from outdoors and is supplied to the room through the expander (22), while the secondary air is an outside air taken from outdoors and then discharged to outdoors through the dehumidifying means (60).
In a nineteenth solution taken in the present invention, based on the twelfth solution, the primary air is a mixed air of a room air taken from the room and an outside air taken from outdoors and is supplied to the room through the expander (22), while the secondary air is a mixed air of a room air taken from the room and an outside air taken from outdoors and is discharged to outdoors through the dehumidifying means (60).
A twentieth solution taken in the present invention is, based on the twelfth solution, provided with preheating means (33) for heating the primary air dehumidified by the dehumidifying means (60) through heat exchange with the primary air compressed by the compressor (21) and then supplying the primary air to the compressor (21).
A twenty-first solution taken in the present invention is, based on the twelfth solution, provided with preheating means (33) for heating the primary air dehumidified by the dehumidifying means (60) through heat exchange with part of the primary air compressed by the compressor (21) and then supplying the primary air to the compressor (21).
A twenty-second solution taken in the present invention is, based on any one of the twelfth to twenty-first solutions, provided with moisture supplying means (41) for supplying moisture to the secondary air not yet supplied to the heat exchanger (30) in order to humidify and cool the secondary air.
A twenty-third solution taken in the present invention is, based on any one of the twelfth to twenty-first solutions, provided with moisture supplying means (42) for supplying moisture to the secondary air in the heat exchanger (30) in order to use latent heat of evaporation of water to cool the primary air in the heat exchanger (30).
In a twenty-fourth solution taken in the present invention, based on the twenty-second or twenty-third solution, the moisture supplying means (41, 42) is arranged to supply moisture to the secondary air through a permeable membrane capable of permeating moisture.
In a twenty-fifth solution taken in the present invention, based on the second solution, heating of a room is effected by supplying the secondary air heated through heat exchange with the primary air in the heat exchanger (30) to the room.
In a twenty-sixth solution taken in the present invention, based on the twenty-fifth solution, the primary air is a room air taken from the room and then discharged to outdoors through the expander (22), while the secondary air is an outside air taken from outdoors and then supplied to the room through the dehumidifying means (60).
In a twenty-seventh solution taken in the present invention, based on the twenty-fifth solution, the primary air is an outside air taken from outdoors and then discharged to outdoors through the expander (22), while the secondary air is an outside air taken from outdoors and then supplied to the room through the dehumidifying means (60).
In a twenty-eighth solution taken in the present invention, based on the twenty-fifth solution, the primary air is a room air taken from the room and then discharged to outdoors through the expander (22), while the secondary air is a room air taken from the room and then supplied to the room through the dehumidifying means (60).
In a twenty-ninth solution taken in the present invention, based on the twenty-fifth solution, the primary air is an outside air taken from outdoors and then discharged to outdoors through the expander (22), while the secondary air is a room air taken from the room and then supplied to the room through the dehumidifying means (60).
In a thirtieth solution taken in the present invention, based on the twenty-fifth solution, the primary air is a room air taken from the room and then discharged to outdoors through the expander (22), while the secondary air is a mixed air of a room air taken from the room and an outside air taken from outdoors and is supplied to the room through the dehumidifying means (60).
In a thirty-first solution taken in the present invention, based on the twenty-fifth solution, the primary air is an outside air taken from outdoors and then discharged to outdoors through the expander (22), while the secondary air is a mixed air of a room air taken from the room and an outside air taken from outdoors and is supplied to the room through the dehumidifying means (60).
In a thirty-second solution taken in the present invention, based on the twenty-fifth solution, the primary air is a mixed air of a room air taken from the room and an outside air taken from outdoors and is discharged to outdoors through the expander (22), while the secondary air is a mixed air of a room air taken from the room and an outside air taken from outdoors and is supplied to the room through the dehumidifying means (60).
A thirty-third solution taken in the present invention is, based on the second solution, provided with selector means (71, 72) for taking in different airs as the primary and secondary airs for each of cooling and heating operations and selecting the primary air from the expander (22) and the secondary air from the dehumidifying means (60) to supply them to the room to thereby allow both the cooling and heating operations.
A thirty-fourth solution taken in the present invention is, based on the thirty-third solution, provided with preheating means (33) for heating the primary air dehumidified by the dehumidifying means (60) through heat exchange with the primary air compressed by the compressor (21) and then supplying the primary air to the compressor (21), and bypassing means (73) for allowing the primary air to bypass the preheating means (33) and to be supplied directly to the compressor (21) during the heating operation.
A thirty-fifth solution taken in the present invention is, based on the thirty-third solution, provided with preheating means (33) for heating the primary air dehumidified by the dehumidifying means (60) through heat exchange with part of the primary air compressed by the compressor (21) and then supplying the primary air to the compressor (21), and bypassing means (73) for allowing the primary air to bypass the preheating means (33) and to be supplied directly to the compressor (21) during the heating operation.
In the first solution, the primary air is supplied to the compressor (22) and so compressed therein as to reach a high temperature. The high-temperature primary air is cooled in the heat exchanger (30) and then so expanded by the expander (22) as to reach a low temperature. This compressor (21) is supplied with the primary air dehumidified by the dehumidifying means (60). Cooling the room is provided by supplying the low-temperature primary air to the room, while heating the room is provided by using heat release from the primary air in the heat exchanger (30).
The humidity medium of the dehumidifying means (60) absorbs moisture in the primary air and releases the absorbed moisture to the secondary air. In other words, the moisture in the primary air is transferred to the secondary air through the humidity medium. During the time, if the relative humidity of the primary air is high to some extent, the humidity medium absorbs moisture. On the other hand, if the relative humidity of the secondary air is low to some extent, the humidity medium releases moisture. Accordingly, even if the primary and secondary airs have equal vapor partial pressures or equal absolute humidities, a difference in relative humidity between both the airs would cause moisture transfer through the humidity medium.
In the second solution, the primary air from the compressor (21) is cooled through heat exchange with the secondary air and then flows toward the expander (22). On the other hand, the humidity medium of the dehumidifying means (60) releases moisture to the secondary air heated in the heat exchanger (30). In other words, the humidity medium releases moisture to the secondary air elevated in temperature and reduced in relative humidity through heat application as a result of heat exchange with the primary air.
In the third solution, the humidity medium absorbs moisture in such a manner that the moisture is adsorbed on the solid adsorbent. Further, the humidity medium releases moisture in such a manner that the moisture is desorbed from the solid adsorbent.
In the fourth solution, the humidity medium is formed of a disc-shaped rotor member (61). A portion of the rotor member (61) absorbs moisture through contact with the primary air in the moisture absorbing section (62). The rotor member (61) is rotatively driven by the drive mechanism so that the portion of the rotor member (61) which has absorbed moisture moves to the moisture releasing section (63). In the moisture releasing section (63), the rotor member (61) releases the moisture through contact with the secondary air. The rotor member (61) as the humidity medium is thereby regenerated. Thereafter, the portion of the rotor member (61) which has been regenerated moves to the moisture absorbing section (62) again and repeats these actions.
In the fifth solution, the solid adsorbent is made of porous inorganic oxide. It is to be noted that the solid adsorbent may be made of particular inorganic oxide alone or may include the inorganic oxide as a main ingredient.
In the sixth solution, the humidity medium absorbs moisture in such a manner that the moisture is absorbed in the liquid absorbent. Further, the humidity medium releases moisture in such a manner that the moisture is desorbed from the liquid absorbent.
In the seventh solution, the liquid absorbent absorbs moisture from the primary air not yet supplied to the compressor (21). This liquid absorbent is heated up into an easy-to-release condition by the high-temperature primary air compressed by the compressor (21), and then released to the secondary air. This moisture release regenerates the liquid absorbent.
In the eighth solution, the primary air and the liquid absorbent come into indirect contact with each other through the hydrophobic porous membrane interposed therebetween. The moisture in the primary air permeates the hydrophobic porous membrane and is then absorbed in the liquid absorbent, whereby the primary air is dehumidified.
In the ninth solution, the liquid absorbent is made of a water solution of hydrophilic organic compound. Examples of organic compound of this kind include ethylene glycol, glycerin and hydrophilic resin.
In the tenth solution, the liquid absorbent is made of a water solution of metallic halide. Examples of metallic halide of this kind include LiCl, LiBr and CaCl2.
In the eleventh solution, the liquid absorbent absorbs moisture of the primary air in the moisture absorbing section (65), whereby the primary air is dehumidified. This liquid absorbent flows through the circulation circuit (64) to reach the moisture releasing section (66). In the moisture releasing section (66), the liquid absorbent releases moisture to the secondary air and is thereby regenerated. The regenerated liquid absorbent flows through the circulation circuit (64) to reach the moisture absorbing section (65) again, and repeats this circulation.
In the twelfth solution, the primary air expanded in the expander (22) to reach a low temperature is supplied to the room, thereby cooling the room.
In the thirteenth solution, an outside air is supplied as the primary air to the dehumidifying means (60). This outside air is dehumidified by the dehumidifying means (60), supplied to the compressor (21), sequentially flows through the compressor (21), the heat exchanger (30) and the expander (22) to reach a low temperature, and is then supplied to the room. On the other hand, a room air is supplied as the secondary air to the heat exchanger (30). This room air passes through the heat exchanger (30), flows into the dehumidifying means (60), takes moisture from the dehumidifying means (60), and is then discharged to outdoors.
In the fourteenth solution, an outside air is supplied as the primary air to the dehumidifying means (60). This outside air is dehumidified by the dehumidifying means (60), is supplied to the compressor (21), sequentially flows through the compressor (21), the heat exchanger (30) and the expander (22) to reach a low temperature, and is then supplied to the room. On the other hand, another outside air is also supplied as the secondary air to the heat exchanger (30). This outside air passes through the heat exchanger (30), flows into the dehumidifying means (60), takes moisture from the dehumidifying means (60), and is then discharged to outdoors again.
In the fifteenth solution, a room air is supplied as the primary air to the dehumidifying means (60). This room air is dehumidified by the dehumidifying means (60), is supplied to the compressor (21), sequentially flows through the compressor (21), the heat exchanger (30) and the expander (22) to reach a low temperature, and is then supplied to the room again. On the other hand, another room air is also supplied as the secondary air to the heat exchanger (30). This room air passes through the heat exchanger (30), flows into the dehumidifying means (60), takes moisture from the dehumidifying means (60), and is then discharged to outdoors.
In the sixteenth solution, a room air is supplied as the primary air to the dehumidifying means (60). This room air is dehumidified by the dehumidifying means (60), is supplied to the compressor (21), sequentially flows through the compressor (21), the heat exchanger (30) and the expander (22) to reach a low temperature, and is then supplied to the room again. On the other hand, an outside air is supplied as the secondary air to the heat exchanger (30). This outside air passes through the heat exchanger (30), flows into the dehumidifying means (60), takes moisture from the dehumidifying means (60), and is then discharged to outdoors again.
In the seventeenth solution, a mixed air of room and outside airs is supplied as the primary air to the dehumidifying means (60). This mixed air is dehumidified by the dehumidifying means (60), is supplied to the compressor (21), sequentially flows through the compressor (21), the heat exchanger (30) and the expander (22) to reach a low temperature, and is then supplied to the room. On the other hand, a room air is supplied as the secondary air to the heat exchanger (30). This room air passes through the heat exchanger (30), flows into the dehumidifying means (60), takes moisture from the dehumidifying means (60), and is then discharged to outdoors.
In the eighteenth solution, a mixed air of room and outside airs is supplied as the primary air to the dehumidifying means (60). This mixed air is dehumidified by the dehumidifying means (60), is supplied to the compressor (21), sequentially flows through the compressor (21), the eat exchanger (30) and the expander (22) to reach a low temperature, and is then supplied to the room. On the other hand, an outside air is supplied as the secondary air to the heat exchanger (30). This outside air passes through the heat exchanger (30), flows into the dehumidifying means (60), takes moisture from the dehumidifying means (60), and is then discharged to outdoors again.
In the nineteenth solution, a mixed air of room and outside airs is supplied as the primary air to the dehumidifying means (60). This mixed air is dehumidified by the dehumidifying means (60), is supplied to the compressor (21), sequentially flows through the compressor (21), the heat exchanger (30) and the expander (22) to reach a low temperature, and is then supplied to the room. On the other hand, another mixed air of room and outside airs is supplied as the secondary air to the heat exchanger (30). This mixed air passes through the heat exchanger (30), flows into the dehumidifying means (60), takes moisture from the dehumidifying means (60), and is then discharged to outdoors.
In the twentieth and twenty-first solutions, the primary air is dehumidified by the dehumidifying means (60), is preheated into a higher temperature condition by the preheating means (33), and is then supplied in this condition to the compressor (21). During the time, all of the dehumidified primary air flows into the preheating means (33) in the twentieth solution, while part of the dehumidified primary air flows into the preheating means (33) in the twenty-first solution. When the temperature of the primary air is higher at the inlet of the compressor (21), it will be elevated to a still higher temperature at the outlet of the compressor (21). Correspondingly, the temperature of the secondary air will also be elevated at the outlet of the heat exchanger (30). Accordingly, the humidity medium of the dehumidifying means (60) will release moisture to the secondary air of higher temperature.
In the twenty-second solution, moisture is supplied to the secondary air by the moisture supplying means (41), and this moisture is then evaporated to cool the secondary air. This cooled secondary air is supplied to the heat exchanger (30) to exchange heat with the primary air.
In the twenty-third solution, moisture is supplied to the secondary air in the heat exchanger (30) by the moisture supplying means (42). In the heat exchanger (30), heat is exchanged between the secondary air and the primary air while moisture is evaporated in the secondary air. Then, latent heat of evaporation of water is used to cool the primary air.
In the twenty-fourth solution, the moisture supplying means (41, 42) adequately supplies moisture to the secondary air through the permeable membrane. This ensures that the supplied moisture evaporates in the secondary air.
In the twenty-fifth solution, the secondary air heat exchanged with the primary air in the heat exchanger (30) to reach a high temperature is supplied to the room, thereby heating the room.
In the twenty-sixth solution, a room air is supplied as the primary air to the dehumidifying means (60). This room air is dehumidified by the dehumidifying means (60), is supplied to the compressor (21), sequentially flows through the compressor (21), the heat exchanger (30) and the expander (22), and is then discharged to outdoors. On the other hand, an outside air is supplied as the secondary air to the heat exchanger (30). This outside air is heated up by passing through the heat exchanger (30), flows into the dehumidifying means (60), is humidified by taking moisture from the dehumidifying means (60), and is then supplied to the room.
In the twenty-seventh solution, an outside air is supplied as the primary air to the dehumidifying means (60). This outside air is dehumidified by the dehumidifying means (60), is supplied to the compressor (21), sequentially flows through the compressor (21), the heat exchanger (30) and the expander (22), and is then discharged to outdoors again. On the other hand, another outside air is also supplied as the secondary air to the heat exchanger (30). This outside air is heated up by passing through the heat exchanger (30), flows into the dehumidifying means (60), is humidified by taking moisture from the dehumidifying means (60), and is then supplied to the room.
In the twenty-eighth solution, a room air is supplied as the primary air to the dehumidifying means (60). This room air is dehumidified by the dehumidifying means (60), is supplied to the compressor (21), sequentially flows through the compressor (21), the heat exchanger (30) and the expander (22), and is then discharged to outdoors. On the other hand, another room air is also supplied as the secondary air to the heat exchanger (30). This room air is heated up by passing through the heat exchanger (30), flows into the dehumidifying means (60), is humidified by taking moisture from the dehumidifying means (60), and is then supplied to the room again.
In the twenty-ninth solution, an outside air is supplied as the primary air to the dehumidifying means (60). This outside air is dehumidified by the dehumidifying means (60), is supplied to the compressor (21), sequentially flows through the compressor (21), the heat exchanger (30) and the expander (22), and is then discharged to outdoors again. On the other hand, a room air is supplied as the secondary air to the heat exchanger (30). This room air is heated up by passing through the heat exchanger (30), flows into the dehumidifying means (60), is humidified by taking moisture from the dehumidifying means (60), and is then supplied to the room again.
In the thirtieth solution, a room air is supplied as the primary air to the dehumidifying means (60). This room air is dehumidified by the dehumidifying means (60), is supplied to the compressor (21), sequentially flows through the compressor (21), the heat exchanger (30) and the expander (22), and is then discharged to outdoors. On the other hand, a mixed air of room and outside airs is supplied as the secondary air to the heat exchanger (30). This mixed air is heated by passing through the heat exchanger (30), flows into the dehumidifying means (60), is humidified by taking moisture from the dehumidifying means (60), and is then supplied to the room.
In the thirty-first solution, an outside air is supplied as the primary air to the dehumidifying means (60). This outside air is dehumidified by the dehumidifying means (60), is supplied to the compressor (21), sequentially flows through the compressor (21), the heat exchanger (30) and the expander (22), and is then discharged to outdoors. On the other hand, a mixed air of room and outside airs is supplied as the secondary air to the heat exchanger (30). This mixed air is heated up by passing through the heat exchanger (30), flows into the dehumidifying means (60), is humidified by taking moisture from the dehumidifying means (60), and is then supplied to the room.
In the thirty-second solution, a mixed air of room and outside airs is supplied as the primary air to the dehumidifying means (60). This mixed air is dehumidified by the dehumidifying means (60), is supplied to the compressor (21), sequentially flows through the compressor (21), the heat exchanger (30) and the expander (22), and is then discharged to outdoors. On the other hand, another mixed air of room and outside airs is also supplied as the secondary air to the heat exchanger (30). This mixed air is heated up by passing through the heat exchanger (30), flows into the dehumidifying means (60), is humidified by taking moisture from the dehumidifying means (60), and is then supplied to the room.
In the thirty-third solution, the primary and secondary airs are selected and supplied to the room by the selector means (71, 72). Then, the low-temperature primary air expanded by the expander (22) is supplied to the room to cool it. Alternatively, the high-temperature secondary air heated in the heat exchanger (30) is supplied to the room to heat it. Further, the selector means (71, 72) allows the compressor (21) and the heat exchanger (30) to each take in a predetermined air depending upon the cooling or heating operation.
In the thirty-fourth and thirty-fifth solutions, during the cooling operation, the primary air is dehumidified by the dehumidifying means (60), preheated into a higher temperature condition by the preheating means (33), and supplied in this condition to the compressor (21). During the time, all of the dehumidified primary air flows into the preheating means (33) in the thirty-fourth solution, while part of the dehumidified primary air flows into the preheating means (33) in the thirty-fifth solution. When the temperature of the primary air is higher at the inlet of the compressor (21), it will be elevated to a still higher temperature at the outlet of the compressor (21). Correspondingly, the temperature of the secondary air will also be elevated at the outlet of the heat exchanger (30). Accordingly, the humidity medium of the dehumidifying means (60) will release moisture to the secondary air of higher temperature. On the other hand, during the heating operation, the primary air dehumidified by the dehumidifying means (60) is allowed to bypass the preheating means (33) by the bypassing means (73) and supplied directly to the compressor (21) in both the thirty-fourth and thirty-fifth solutions.
Thus, according to the present invention, dehumidification of the primary air can be implemented by moisture absorption and release of the humidity medium based on the difference in relative humidity between the primary and secondary airs. Specifically, if the relative humidity of the primary air is high to some extent, the humidity medium absorbs moisture. If the relative humidity of the secondary air is low to some extent, the humidity medium releases moisture. Accordingly, even if the primary and secondary airs have equal vapor partial pressures or equal absolute humidities, a difference in relative humidity between both the airs would cause moisture transfer through the humidity medium. Therefore, dehumidification of the primary air is not limited to after it has been compressed by the compressor (21), unlike the case of dehumidifying it using the conventional vapor isolating membrane, and is possible also before it is supplied to the compressor (21). As a result, layout constraints of the dehumidifying means (60) can be reduced, which enhances the design flexibility.
Further, since there is no need for such dehumidification between the compressor (21) and the expander (22) as conventionally done, an easy and reliable seal is provided between the compressor (21) and the expander (22) while the construction is maintained simply. This prevents leakage of the compressed air and ensures that the efficiency is maintained. Furthermore, air leakage does not result directly in loss of input to the compressor (21) so long as it occurs upstream of the compressor (21). Therefore, the portion upstream of the compressor (21) does not need as complete a seal as between the compressor (21) and the expander (22). This also provides simplified construction.
Still further, since the dehumidifying means (60) releases moisture, which it has taken up from the primary air, to the secondary air, this eliminates the need to dispose of the moisture as a drain. Therefore, any structure for drainage is not required, which simplifies the construction.
According to the second solution, moisture in the humidity medium can be released to the secondary air which has been reduced in relative humidity by the passage through the heat exchanger (30). This ensures that the moisture is released from the humidity medium to adequately regenerate the humidity medium, whereby it is ensured that the primary air is dehumidified. Further, in conducting the heating operation by supplying the secondary air from the humidity medium to the room, the secondary air can be humidified by the moisture removed from the primary air. Accordingly, energy of the moisture in the primary air can be recovered to the secondary air, which provides enhanced energy efficiency.
According to the third to eleventh solutions, the humidity medium of the dehumidifying means (60) can be formed using the solid adsorbent or the liquid absorbent. Particularly according to each of the fourth and eleventh solutions, the dehumidifying means (60) can be formed properly for each particular humidity medium.
According to the twelfth to twenty-fourth solutions, cooling of the room can be implemented by supplying to the room the primary air having reached a low temperature through the sequential passage through the compressor (21), the heat exchanger (30) and the expander (22).
Particularly in the thirteenth, fifteenth, seventeenth and nineteenth solutions, a room air or a mixed air containing the room air is supplied to the heat exchanger (30). In this case, during the cooling operation, the room air is lower in temperature than the outside air. Therefore, the primary air can be cooled to a still lower temperature in the heat exchanger (30) and therefore the air temperature at the inlet of the expander (22) can be reduced. Further, according to the twenty-second to twenty-fourth solutions, moisture is supplied to the secondary air so that the primary air can be cooled to a still lower temperature in the heat exchanger (30). Therefore, the air temperature at the inlet of the expander (22) can be reduced. As a result, each of the above solutions enables reduction in the input to the compressor (21) while maintaining the refrigerating capacity and thereby provides improved. COP (coefficient of performance).
In buildings or the like, the rooms must be not only air conditioned but also ventilated. In such a case, if an outside air is used as the primary air while a room air is used as the secondary air as in the thirteenth solution, the rooms can be ventilated while being cooled. Further, since the primary air is cooled by the room air as the secondary air in the heat exchanger (30), cold heat can be recovered from the room air being discharged to outdoors for ventilation. As a result, energy loss involved in ventilation can be reduced.
According to the twentieth and twenty-first solutions, the temperature of the primary air to be supplied to the compressor (21) can be elevated to a higher degree as compared with the case where it is supplied thereto directly from the dehumidifying means (60). The temperature of the secondary air at the outlet of the heat exchanger (30) can be correspondingly elevated. As a result, regeneration of the humidity medium can be achieved with certainty by the secondary air of higher temperature and low humidity.
According to the twenty-fifth to thirty-second solutions, heating of the room can be implemented by supplying to the room the secondary air which has been heated up by the passage through the heat exchanger (30) and moisturized by the passage through the dehumidifying means (60). Further, as described above, in buildings or the like, the rooms must be not only air conditioned but also ventilated. In such a case, if a room air is used as the primary air and an outside air is used as the secondary air as in the twenty-sixth solution, the rooms can be ventilated while being heated. Furthermore, since the primary air of a room air and the secondary air to be supplied to the room are heat exchanged with each other in the heat exchanger (30), hot heat can be recovered from the room air being discharged to outdoors for ventilation. As a result, energy loss involved in ventilation can be reduced.
According to the thirty-third to thirty-fifth solutions, the cooling and heating operations can be selectively conducted. In addition, according to the thirty-fourth and thirty-fifth solutions, during the heating operation, the bypass means (73) can allow the primary air to bypass the preheating means (33) for supply to the compressor (21).